This invention relates to decorative articles, and more particularly relates to methods for manufacturing wall hangings and similar decorative articles from plow disc blades.
It is well known in the prior art that circular plow disc replacement blade are used to repair plows by replacing blades thereof on a farm and the like. Such a circular plow disc blade is typically constructed of steel with either a smooth or a notched, serrated edge. As is well known to those skilled in the farming art, such plow disc blades have a substantially rectangular center hole through which they are typically cascaded together by being disposed axially on a bar which is disposed orthogonally behind a tractor and pulled thereby to till soil and rotate crop silage.
Thus, the use of such plow discs has heretofore been limited to the repair of plows by replacing the damaged blades thereof. The manufacture of decorative wall hangings and the like from plow disc blades has been unknown in the prior art.
It is also well known in the prior art that a hand-held torch is a useful device for cutting forms and shapes in a metal work piece. It is also well known to those skilled in the art that the limitations and disadvantages of the conventional oxyacetylene torch, including slow heating of metallic surfaces and inaccurate cutting behavior, have been substantially overcome by the plasma torch.
For example, in U.S. Pat. No. 2,976,907, Harvey discloses a magnetic forming method, and apparatus therefor, to shape the surface of a metallic work piece using the magnetic field of high flux density. In this method, current induced in the work piece produces a sufficient impulsive force to effect deformation of the surface thereof. More particularly, plasma received at the portion of the work piece to be shaped, is accelerated by a magnetic field to transfer energy thereto. Accordingly, the impinging plasma provides sufficient mechanical force to alter the work piece's shape. Banas, et al., in U.S. Pat. No. 4,122,240, generally discuss the application of lasers for deep melting of a metallic surface to effectuate welding and cutting thereof. Similarly, Dube, in U.S. Pat. No. 4,767,102, discloses a conventional plasma arc torch of lightweight design with a capacity for accurate cutting of prescribed shapes in metallic objects. Providing means for effectively guiding the nozzle of plasma torch under the influence of an electric motor stored in the handle thereof, the Dube device enables the nozzle to travel along a template surface, thereby cutting straight, curved and arcuate lines without limitation or the necessity for special tools.
This improved plasma cutting technology has been used to cut holes in metal samples and to make linear cuts in thick metal plates. As an example, U.S. Pat. No. 3,153,133, Ducati discloses an apparatus and method for cutting electrically-conductive work pieces by using an electrical plasma jet torch adapted to direct jets of high temperature plasma against opposite sides of a work piece. This methodology provides the ability to efficiently make ridge-free cuts even in thick metal plates.
In U.S. Pat. No. 4,778,155, Suchevich, improves upon the prior plasma torch art of cutting irregularly shapes or large circular holes in metal work pieces, by teaching a torch-aiming assembly for cutting holes of predetermined size in these work pieces, whereby small, accurate holes may be cut therein. Similarly, Tylko, in U.S. Pat. No. 4,60,640, teaches a method of cutting a multiplicity of pieces in a predetermined pattern from a work piece, whereby a plasma torch and metal work piece move relative to each other.
Accordingly, these developments and advantages of the prior plasma torch art have been applied to the manufacture of wall hangings and other decorative articles with the present invention, and improved means and techniques are provided which are especially useful for accurately and efficiently cutting a diversity of shapes into the surface of a conventional plow disc blade, and for the manufacture of a new and improved decorative article therefrom.